<PRE><B>Question 190415</B>
Use composition of functions to prove that it does matter what order you use these discounts at the store to get the greatest toal discount. The coupons are for $25 and 40% discount on your total purchase price.
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Let f(x) = x-25
Let g(x) = 0.75x
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f[g(x)] = f[0.75x] = 0.75x-25
g[f(x)] = g[x-25] = = 0.75(x-25) = 0.75x-18.75
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Evaluate if x = $100
f[g(100)] = 0.75*100-25 = $50
g[f(100)] = 0.75*100-18.75 = $56.25
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Cheers,
Stan H. </PRE>